Our modern highly mobile society has necessitated the use of paved surfaces such as roads, sidewalks, and pathways. These paved surfaces are typically of aggregate composition such as either asphalt pavement or concrete. Unfortunately, wear and seasonal changes lead to damage. The damage is usually to localized areas making pavement patching an economical alternative to complete pavement replacement. The damaged areas are typically irregularly shaped depressions containing broken and pulverized aggregate pavement material. These damaged areas are typically repaired manually, using hot or cold asphalt composition mixtures.
Damaged pavement presents several problems. Once the paved surface is damaged, additional damage becomes more likely. Water and environmental contaminants are able to seep into the aggregate composition further weakening it and setting the stage for more damage. Vehicle tires that pass over damaged areas are often jolted by a recess or ridge causing the vehicle to bounce or jolt, thereby exerting additional force on the surrounding pavement and spreading the damage. Damaged areas also affect the safety of vehicles and pedestrians. Recesses encountered by a vehicle may upset the stability of the vehicle and surprise the driver increasing the likelihood of an accident. Larger recesses may cause damage to vehicles directly such as blown tires, suspension damage or bent wheels. Pedestrians encountering a recess may trip and be injured. Even small damaged areas increase the need for driver and pedestrian alertness, and make the road or pathway less pleasant to use. Therefore, there is a need for economical and effective methods to repair damaged paved surfaces.
The typical repair is made using a truck for delivering a premixed filler material to the damaged area. A worker then shovels the material from the truck into the damaged areas and levels the material with the back of the shovel. This time honored method of pavement patching is both labor intensive and dangerous.
The typical repair approach has additional drawbacks. After a worker fills a damaged area, traffic tends to squash the pavement composition down, thereby reshaping it. As shown in FIG. 2A, the pavement composition often gets pushed towards one end of the hole creating a ramp. The arrow in FIG. 2A indicates the direction of traffic travel. The pavement composition is pushed in the direction of travel to the end of the hole creating the ramp which can be dangerous to passing cars and motorcycles. The ramp can be nearly as upsetting to the vehicles as the original damaged area.
It is preferable that a recess be filled in the manner shown in FIG. 2B. As shown, the recess is filled such that there is an extra portion of filler material adjacent the leading edge of the recess. By filling the recess in this manner, the repair is ready to be run over by vehicular traffic. As the traffic compresses and redistributes the filler material, the repair will become flat as the extra portion of filler material is pushed forward and the filler material becomes compressed. This prevents the formation of a ramp, or at least reduces the size of a ramp, improving the performance of the repair. Ideally, a worker using a shovel can create a repair as shown in FIG. 2B. However, a worker is typically working under less than ideal conditions and it is unlikely that he or she can repeatedly and reliably create an optimal repair. For this reason, there is a need for an apparatus that can repeatedly and reliably repair recesses in paved surfaces in the proper manner.
While the idea of using a sensor to control the metering of paving material is known to the art, as taught for example in U.S. Pat. No. 5,452,696, the ability to meter cementitious or aggregate paving material to a damaged pavement surface has heretofore not been contemplated. It is thus an object of the current invention to provide an apparatus and method for delivering aggregate paving materials in proportional amounts to recesses in a pavement surface while continuously moving.
The use of a series of dispensing nozzles for the automated delivery of liquids to damaged areas of a pavement surface, is taught in U.S. Pat. No. 5,294,210. However, this invention relies on the use of electronic sensors and a computer to control the dispensers. It is an object of the present invention to avoid the need for electronic sensors and computer control in the repair of pavement.